FBI agents are not paid in hourly wages, they are paid through the federal government system GS ratings which provides agents an annual salary rating for years served.
The tariff of the United States, like all actual protective tariffs, is partly revenue and partly protective, its original purpose of yielding revenue having been subordinated to that of giving protection, until it may now be best described as a protective tariff yielding incidental revenue.
A fee charged (levied) by a government on a product, income, or activity. If tax is levied directly on personal or corporate income, then it is a direct tax. If tax is levied on the price of a good or service, then it is called an indirect tax. The purpose of taxation is to finance government expenditure.